Contour Plots
 | 178 - Analysis of SR Motor I-Psi Characteristics
| Module:DP | 2013-01-23 | With the skyrocketing prices of rare earth magnets, expectations have been rising for SR (switched reluctance) motors because they have a motor format that does not use permanent magnets. SR motors have a simple structure that can achieve solid performance at a low price. However, torque generation depends only upon the saliency between the stator and rotor, so torque variations are extremely large and cause vibration and noise, meaning that the use applications are limited. On the other hand, because of the skyrocketing prices of rare earth metals, the improvement in current control technology, the possibility of optimized designs thanks to magnetic field analysis, and the rising ability to reduce challenges, SR motors are being re-examined.
SR motors operate using the nonlinear region of a magnetic steel sheet, so because the inductance displays nonlinear behavior, it is impossible to carry out advanced projections that are accurate with calculation methods that follow linear formulas. Consequently, it becomes necessary to use the finite element method (FEM), which can handle nonlinear magnetic properties in material and minute geometry.
This example presents an evaluation of flux linkage, inductance and torque for each rotor position when the flowing current value is changed.
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  | 177 - Torque Characteristic Analysis of a Three Phase Induction Motor | Module:DP,LS | 2012-08-31 | An induction motor is a motor in which the rotating magnetic field of the stator coils causes induced current to flow in an auxiliary conductor, which exerts force on the rotor in the rotational direction and causes it to spin. Induction motors are widely used in everything from industrial machines to home appliances because they have a simple construction and are small, light, affordable, and maintenance-free.
It is possible to drive an induction motor so that its slip is constant by adjusting the voltage or current against load variations. When this happens, each characteristic changes with influence from magnetic saturation and leakage flux because of the excitation variations in a specific slip.
This Application Note explains how to obtain the torque characteristics in an induction motor when the current amplitude has been changed in a specific slip.
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 | 176 - Drive Characteristic Analysis of a Three-Phase Induction Motor | Module:DP,LS | 2012-08-31 | An induction motor is a motor in which the rotating magnetic field of the stator coils causes induced current to flow in an auxiliary conductor, which exerts force on the rotor in the rotational direction and causes it to spin. Induction motors are widely used in everything from industrial machines to home appliances because they have a simple construction and are small, light, affordable, and maintenance-free.
In an induction motor, the current induced by the auxiliary conductor exerts a large influence on its characteristics. It also causes strong magnetic saturation in the vicinity of the gap, in particular. This is why a magnetic field analysis based on the finite element method (FEM) is useful when investigating the motor's characteristics for a design study.
This Application Note explains how to confirm drive characteristics such as torque, loss, and efficiency in an induction motor when its rotation speed changes.
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 | 172 - High-Frequency Induction Heating Analysis of a Test Piece (Rotational Induction Hardening)
| Module:FQ,HT | 2012-07-31 | Machine parts like shafts and gears are made to be resistant to wear and tear. This is accomplished by giving them a certain degree of flexibility by maintaining their interior toughness while increasing the hardness of their surfaces. By using high-frequency induction heating, which is a type of surface hardening method, the part is heated rapidly on only its surface by a high frequency power source. This process also has many other benefits, such as providing a clean working environment because it uses electrical equipment, being very efficient, and providing uniform results for each product. This is why it is being aggressively implemented in the field.
With induction hardening like the kind used on the work piece in this analysis, the main requirement is to heat a given surface uniformly and increase rigidity. The high-frequency's varying magnetic field produces eddy currents with an offset in the surface of the work piece, so handling the phenomena inside the work piece with a numerical analysis based on the finite element method (FEM) is the most effective means analyzing the process in detail.
This Application Note explains how to create a numerical analysis model when obtaining the optimum coil geometry, current conditions (power supply frequency, current value), and rotation speed. It also shows how to evaluate whether the target temperature distribution is being achieved by analyzing the elevated temperature process.
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 | 167 - Iron Loss Analysis of a Three Phase Induction Motor UP!
| Module:DP,LS | 2013-06-17 | An induction motor is a motor in which the rotating magnetic field of the stator coils causes induced current to flow in an auxiliary conductor, which produces force in the rotational direction.
Induction motors are widely used in everything from industrial machines to home appliances because they have a simple construction without parts that experience wear from abrasion, and can be used simply by connecting them to a power source.
Improved efficiency in induction motors is an important theme. Iron loss, a cause of lower efficiency along with primary and secondary copper loss, must be reduced in order to improve efficiency. The relative importance of iron loss tends to grow especially with higher rotations due to the inverter drive, so it is helpful to estimate the complex iron loss distribution inside the core.
This Application Note presents an example of how to find the iron loss in the stator core and rotor core at a rotation speed of 3,300 r/min.
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 | 163 - Torque-Current Curve Analysis of an SPM Motor UP!
| Module:DP | 2013-06-17 | One of the fundamental properties of a permanent magnet synchronous motor is the relationship between its current and torque (torque-current curve). The torque generated at each current value is uniform with increases in current up to a certain point, so the torque increases in a linear fashion. However, magnetic saturation effects occur with further current increases, and the torque generated with each increase in current begins to drop off.
Because a permanent magnet synchronous motor's torque-current curve is highly susceptible to saturation effects in the motor's magnetic circuit, it is helpful to obtain the torque-current curve with a magnetic field analysis taking saturation into account in order to evaluate the motor's design and drive characteristics.
This Application Note presents how to obtain the torque-current curve as a basic property of one type of permanent magnet synchronous motor, the surface permanent magnet synchronous (SPM) motor.
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 | 158 - Superimposed Direct Current Characteristic Analysis of a Reactor That Accounts for Minor Hysteresis Loops
| Module:FQ,ST | 2012-07-31 | High-frequency reactors used in equipment like DC-DC converters have a high-frequency current accompanying the switching direct current. The reactor's performance requires a stable inductance in a wide direct current region that is superimposed by alternating current components. If there is only a direct current, the magnetic flux is generated against the external magnetic field, following the magnetic steel sheet's DC magnetization curve. However, when there is a current waveform whose high-frequency components are superimposed on the direct current component, the response displays a minor loop against the external magnetic field. The values of the inductance in the reactor can have significant differences depending on the method used to measure them. This can make it difficult to carry out a performance prediction during an actual state of operation.
In order to handle the responsiveness of a magnetic field against a current waveform that is superimposed by a higher harmonic with a small amplitude for the direct current component, a magnetic field analysis that accounts for material modeling needs to be carried out. With a magnetic field analysis, it is possible to analyze the machine characteristics from the magnetic flux density distribution.
This Application Note presents the use of the frozen permeability condition to obtain the superimposed direct current characteristic that includes minor hysteresis loops of a high-frequency reactor.
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 | 157 - Analysis of Eddy Currents in an IPM Motor Using the Gap Flux Boundary UP!
| Module:DP,FQ | 2013-06-17 | It is becoming increasingly common for permanent magnet motors to use rare earth magnets in order to achieve higher output density because they have a high energy product. Neodymium rare earth magnets have a high electric conductivity because they contain a great deal of iron, so when a varying magnetic field is applied to them they produce joule loss from eddy currents. IPM structure adoption and field weakening controls have become prevalent in recent years in order to allow faster rotation. This has led to an increase in the frequencies and fluctuation ranges of the varying fields applied to magnets, resulting in a corresponding increase in joule losses. By dividing the magnet like one would a laminated core to control eddy currents, one can obtain a method of raising the apparent electric conductivity while lowering the eddy currents. Armature reactions in the stator occur before the eddy currents produced in the magnet, so the eddy currents are determined by: The slot geometry of the stator core, the geometry of the rotor, the nonlinear magnetic properties of the core material, and the current waveform that flows through the coil.
In order to examine these kinds of magnet eddy currents ahead of time, one has to be precise when accounting for things like these various geometries and material properties. This is why a magnetic field simulation using the finite element method (FEM), which can account for them, would be the most effective.
This Application Note explains how to use the gap flux boundary condition to evaluate the eddy current loss in the magnet by changing the number of magnet divisions. This will make it possible to obtain effective results in a shorter period of time than with a normal transient response analysis.
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 | 156 - Segregation Analysis of Torque Components for an IPM Motor
| Module:DP | 2012-07-31 | IPM motors are often used as high performance motors because they are highly efficient and their structure makes it possible to achieve a wide range of operation. They are able to achieve high efficiency because they obtain maximum total torque by using their controls to adjust their magnet and reluctance torques. For this reason, it is important to find out the distribution of both of these torques during operation when the IPM motor is being designed. The motor's detailed geometry and the material's nonlinear magnetic properties need to be taken into account to obtain the torque characteristics, and it is even more difficult to segregate the torque into two components by using manual calculations.
In order to proceed with the design while looking into how much each one contributes, it needs to be studied with an electromagnetic field analysis that uses the finite element method (FEM).
In this Application Note, the torque components are separated and the magnetic flux density distributions created by each magnetomotive force are confirmed.
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 | 154 - Calculation of Equivalent Circuit Parameters in a Three-Phase Induction Motor | Module:DP | 2012-08-31 | An induction motor is a motor in which the rotating magnetic field of the stator coils causes induced current to flow in an auxiliary conductor, exerting force on the rotor in the rotational direction and causing it to spin. Induction motors are widely used in everything from industrial machines to home appliances because they have a simple construction and are small, light, affordable, and maintenance-free.
An induction motor's characteristics are influenced by leakage reactance and resistance, including resistance on the secondary side. These are referred to as equivalent circuit parameters, and they are important because they characterize a device's properties.
Equivalent circuit parameters are greatly affected by both the current distribution induced in the auxiliary conductor and the magnetic saturation near the gap, so a finite element analysis (FEA) needs to be run in order to investigate these characteristics with precision.
This Application Note explains how to obtain the secondary resistance, leakage inductance, and excitation inductance of an induction motor when its power supply frequency has been changed with regard to its voltage and current controls.
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 | 149 - Analysis of Magnetic Blowout Force Acting on the Arc of a Switching Gear
| Module:TR | 2011-02-28 | Metal vapor is produced from the contacts of a switching gear during cutoff and a plasma arc forms. The structure of the contact rings is innovated to produce a magnetic field that expands the arc and prevents vacuum deposition caused by the arc. The arc expands by the Lorentz force that is produced.
This example presents the use of a magnetic field analysis to obtain the current density and Lorentz force of the switching gear and the force expanding the arc.
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 | 148 - Loss Analysis of a Power Transformer (Flyback Converter) | Module:DP,LS,TR,TS | 2012-08-31 | A flyback converter is a well-known system for small capacity power supplies in the several-dozen W class. They are cheap and have a simple structure, so they are widely used as converters for pressurization in home appliances. In recent years there has been a trend toward making small-scale switching transformers even smaller and higher-frequency, so it is not rare to see converters using the flyback system drive 100 kHz or more.
Because of the higher frequencies and smaller scales of transformers, an important challenge of how to control their heat generation has emerged in the design process. The losses that produce heat can be separated into copper loss in the coil and iron loss in the core. Copper loss is distributed inside of the coils because of the proximity effect, which is caused by influence from the skin effect and leakage flux. This means that local heat generation in the coils becomes a problem.
Iron loss also has a complex distribution because it depends on the magnetic flux density distribution that accounts for the core's magnetic saturation, so the core's local heat generation becomes a problem as well.
A magnetic field analysis simulation based on the finite element method (FEM) can precisely evaluate the complex loss distributions of the coil and core, so it is optimal for an advance study of a switching transformer's thermal design.
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 | 146 - Analysis of Stray Loss in a Transformer
| Module:FQ,HT,LS | 2012-07-31 | Transformers are made to be used long-term, so it has become an important design policy to control running costs from losses. These losses include copper loss in the coil and iron loss in the core. In high-capacity transformers, however, there is also stray loss in the tank from flux leakage from the core. From a safety standpoint, companies want to contain the heat produced from stray losses in the tank to well below the standards required for heat resistant design because they anticipate injuries from people touching the tank itself.
Predicting these losses and the heat that they generate is a vital component of transformer design, but it is difficult to estimate them from desktop calculations, so evaluations and detailed analyses using the finite element method (FEM) are indispensible.
This Application Note explains how to obtain losses in a transformer tank and use them to evaluate the temperature distribution in each part.
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 | 143 - Inductance Analysis of an Air Core Coil
| Module:ST | 2011-01-17 | Air core coils that have a smaller inductance than a coil with a core are used in high-frequency filters and oscillators.
The inductance needs to be investigated thoroughly because any change to the dimensions can affect the inductance.
This example presents the use of a magnetic field analysis to compare the analyzed inductance of an air core coil with the inductance that is theorized.
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 | 142 - Press Fit Analysis of a Divided Core
| Module:DP,DS,LS | 2013-02-28 | Smaller size and higher output are being demanded of the motors used for applications such as air conditioning compressors. One production technique for achieving this is a higher lamination factor in divided cores. The stress caused by press-fitting a divided stator core into a frame is known to increase iron loss in a motor if magnetic steel sheet is used for the core.
Iron loss is affected by magnetic flux density and stress. Specifically, it increases in areas of high magnetic flux density with high frequency, and in areas of high stress. Further, the stress caused by press fitting has its own distribution, and is particularly large in the core and back yoke. So, in order to evaluate the iron loss with good accuracy, it is necessary to correctly obtain the magnetic flux density distribution, time variations, and stress distribution.
This Application Note presents how to use the Press Fit condition to model an analysis of the stress from fitting a core to a frame, and then obtain the iron loss density of an IPM motor under no load, with and without accounting for the stress.
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 | 139 - Power Transmission Analysis Using Magnetic Resonance Phenomena UP!
| Module:FQ | 2013-06-17 | Recently, magnetic resonance is gaining attention as a new type of wireless transmission technology. Magnetic resonance differs from conventional types of electromagnetic induction transmission that are widely used today in that the axes of the transmission and receiving coils do not need to be aligned and in that it allows efficient transmission at a distance of several meters. A design for the coil geometry and circuit that is optimized for the frequency being used is necessary to make the transmitting and receiving sides resonate and thus transmit power.
It is very difficult to use measurement to visualize how magnetic field is being generated, and is therefore transmitting power, in the space between the transmitting side and the receiving side. Reproducing the power transmission state using analysis can help with designing optimized coils.
This Application Note presents how to confirm the power transmission efficiency and the magnetic flux density distribution.
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 | 138 - Vibration Analysis of an SR Motor UP!
| Module:DP,DS | 2013-06-17 | There are high hopes for SR motors to provide robustness and low cost, thanks to their relatively simple construction without permanent magnets. However, the large electromagnetic force produced by the saliency of their stator and rotor causes vibration and noise.
The electromagnetic force working in an SR motor causes vibration and noise as an electromagnetic excitation force. Vibration and noise are caused when this electromagnetic excitation force resonates with the motor's eigenmode. In order to evaluate this phenomenon with acceptable precision, it is necessary to accurately ascertain the distribution of the electromagnetic force acting on the stator core, which is the source of radiated sound, and to obtain the eigenmode of the entire motor including its connected case.
This Application Note presents an example of how to obtain the electromagnetic force generated in the stator core of an SR motor and evaluate the sound pressure by linking it to the motor's eigenmode.
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 | 133 - Thermal Analysis of a Three-phase Transformer
| Module:HT | 2011-02-28 | Recently, the growing demand for energy conservation and highly efficient transformers is raising the importance of reducing losses.
The iron loss of the core and the copper loss of the winding cause a raise in temperature and reduction in the efficiency of a transformer because the energy is released as heat.
Evaluating the heat generated by the iron and copper losses through simulation becomes advantageous when designing a transformer.
This example presents the use of a thermal analysis to obtain the temperature distribution of the heat generated by the iron losses and copper losses of the three-phase transformer.
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 | 132 - Loss Analysis of a Three-phase Transformer UP!
| Module:FQ,LS | 2013-06-17 | Mid- and large-sized power transformers need to be able to operate over the long term, so they are always required to control running costs from losses. Iron loss is one of the main losses in a transformer, and it can lead to temperature increases and efficiency decreases because it consumes electric power as heat in a magnetic material.
Using finite element analysis (FEA) to confirm the distribution of iron loss density makes it possible to study a transformer's local geometry during design. Further, evaluating the ratio and distribution of the iron and copper losses through FEA becomes advantageous when designing a transformer.
This note presents how to obtain the iron and copper losses of a three-phase transformer.
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 | 130 - Thermal Conductivity Analysis of Basic Geometry
| Module:HT | 2011-01-17 | In recent years, the importance for methods to handle heat is growing as electrical equipment is miniaturized and designed for high power.
The thermal conductivity and heat transfer coefficient needs to be modeled correctly to accurately evaluate the heat dissipation characteristics of electrical equipment. Therefore, if each part can be modeled correctly, the characteristics of the entire device can be evaluated.
This example presents the use of a thermal analysis to obtain the thermal conductivity of each part using basic cubes assuming they are a rotor core and stator core of a rotating machine. The results for each part are evaluated, and then compared to the theoretical calculation to evaluate their accuracy.
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 | 128 - Structural Analysis of a Cantilever
| Module:DS | 2011-01-17 | The importance of strength design for devices is growing with the miniaturization and flattening of electrical equipment and measures to reduce vibrations are in even greater demand.
To understand the characteristics of electrical equipment, the vibration characteristics and strength of each part that make up the device need to be accurately evaluated. Therefore, the phenomenon of each individual part needs to be correctly analyzed first.
This example presents the use of a structural analysis to obtain eigenmodes and displacement that has a concentrated load for 3 types of mesh models of a simple cantilever. These results are then compared to the theoretical values.
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 | 127 - Resistance Heating Analysis of Steel
| Module:FQ,HT | 2013-04-26 | Deformation occurs when large metal parts such as shafts undergo machining, causing their material properties to worsen. Because of this, these material properties are restored by eliminating machining deformations using thermal processing, which returns the metal structure to its standard condition. It is necessary to heat the whole part to the same temperature in order to restore the metal's overall properties with thermal heating, and ohmic heating is often used for this purpose. It is helpful to measure the temperature distribution in advance with an investigation of heating conditions.
Evaluation with analysis based on the finite element method (FEM) is necessary to find whether a product with a 3D geometry is heated uniformly by a given electrode configuration.
This Application Note presents how to obtain the temperature distribution, temperature variations, and heat flux distribution in a body heated by ohmic heating.
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 | 124 - Cogging Torque Analysis of an SPM Motor Accounting for an Varied Stator Diameter UP!
| Module:DP,DS | 2013-06-17 | When a motor is constructed, the diameter of the stator becomes uneven because of fabrication errors and shrink fitting. It is advantageous to investigate the uneven diameter of the stator because it largely effects the cogging torque.
This example presents the use of a structural and magnetic field analysis to obtain the cogging torque with stator teeth that have an uniform and varying diameter based on the displacement obtained with a stress analysis.
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 | 123 - Thermal Analysis of a Choke Coil
| Module:HT,TS | 2012-07-31 | A choke coil is an electric component that is intended to filter high-frequency current. The current generated in the choke coil has offsets caused by the skin effect, proximity effect, and leakage flux near the gap, so it is distributed both inside of and between the wires. Iron loss generated in the core is also distributed by offsets in the core's magnetic flux density.
Iron loss in the choke coil's core and copper loss in its coil become a heat source in addition to reducing efficiency, so they need to be understood and reduced from a heating design standpoint. An analysis using the finite element method (FEM) is effective in getting more information about the design by quantitatively evaluating the heat generation phenomena with copper and iron losses as the heat sources.
This Application Note shows the use of a thermal analysis to obtain the temperature distribution using the iron losses and copper losses in the choke coil as the heat source.
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 | 122 - Inductance Analysis of an IPM Motor - d/q-axis Inductance Obtained by Actual Measurement -
| Module:DP | 2013-01-28 | Evaluating the inductance characteristics along the d/q-axis is important when analyzing the saliency of a rotor in an IPM motor. With actual measurements, it is possible to calculate the inductance in the d-axis and q-axis by measuring the no-load magnetic flux or the voltage and current with a three-phase current flowing when the motor is in actual operation. If it cannot be measured while the motor is operating, an LCR meter can be entered in two phases when the rotor is in a stationary state. However, current conditions are different between three phases and two phases, so the motor will express different characteristics during actual drive, especially when it is strongly affected by magnetic saturation. For this reason, the analysis contents need to be determined according to the situation of the actual measurements when comparing the measurements with an analysis.
This Application Note presents an analysis that obtains d/q-axis inductance in an IPM motor while assuming actual measurements in a stationary rotor.
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 | 121 - Output Analysis of a Salient-Pole Synchronous Generator
| Module:DP | 2013-04-26 | Salient-pole synchronous generators are used in hydroelectric generators and the like. Power is generated in the stator coils (armature) by a field current flowing in the rotor coils and the rotor rotating.
Reactions occur between the field current and the armature current that either strengthen or weaken the magnetic flux depending on the power factor of the connected load of a salient-pole synchronous generator. This causes the operating point of the magnetic circuit inside the generator to change, which affects the output. The core normally has nonlinear magnetic properties, so an evaluation of the magnetic circuit with magnetic field analysis, which can handle nonlinear magnetic properties, is useful.
This Application Note presents the use of a magnetic field analysis to obtain the magnetic flux density distribution, no-load saturation curve, and output of a salient-pole synchronous generator.
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 | 120 - Thermal Demagnetization Analysis of an SPM Motor
| Module:DP | 2013-04-26 | Exactly how to resolve the problem of rising temperatures is a vital issue when trying to achieve an improvement in a motor's efficiency and output. Among the materials used in a motor, the magnet experiences the greatest variations in properties in relation to temperature. In the case of rare-earth magnets, demagnetization can occur within tens of degrees above 100 deg C. Whether they demagnetize or not depends on the reverse magnetic field applied and the temperature. They still have some resistance if either the temperature is raised only or if a reverse magnetic field is applied only, but the combination of the two causes a great reduction in resistance. A large current flows in the coils when the motor is overloaded and is producing a lot of torque, which leads to a large reverse magnetic field and heat, increasing the possibility of demagnetization. Solutions to this problem include heat-resistant magnets and increased motor size, but these lead to trade-off issues during the design stage because of the larger size and higher cost.
In order to carry out a precise evaluation of demagnetization, it is necessary to get a definite grasp of areas where a reverse magnetic field occurs and the materials' demagnetization properties. With magnetic field analysis simulation using the finite analysis method (FEM), it is possible to calculate the reverse magnetic field and determine whether magnets and other parts demagnetize due to reverse magnetic field, taking material demagnetization properties into account.
This Application Note presents how to change the temperature of permanent magnets in an analysis, and then evaluate the effects on the torque waveform, magnetic flux density distribution, etc.
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 | 119 - Torque Characteristic Analysis of a Three Phase Wound Rotor Induction Motor
| Module:DP | 2011-02-28 | A wound rotor induction motor is a motor that produces torque in the secondary coil through the interaction of the rotating magnetic field and the current induced in the secondary coil by the rotating magnetic field of the stator coil. Because an induced current flows through the coil, the electromagnetic force can be utilized and regenerated through a slip ring.
The current induced in the secondary coil effects the performance of the wound rotor induction motor.For this reason, it is important to evaluate the current that is induced.
This example presents the use of a magnetic field analysis to obtain the current density distribution and the slip versus torque curve of a three-phase wound rotor induction motor.
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 | 118 - Thermal Analysis of a Busbar
| Module:FQ,HT | 2011-01-17 | Current is carried through busbars, or wire bondings, as a supply line of electrical power.
Parts, such as components used in inverters to handle variable frequencies, produce an increased amount of heat due to the resistance cause by a skin effect that increases as the frequency of the current flowing through the circuit gets higher.
A design that accounts for the heat and temperature distribution of each frequency is vital because the excess heat causes a reduction in efficiency or damages the device.
The temperature distribution can be evaluated by treating the Joule losses obtained from the magnetic field analysis as the heat source.
This example presents the use of a coupled magnetic field and thermal analyses to obtain the temperature distribution in a busbar when the frequency of the power supply is changed.
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 | 117 - Iron Loss Analysis of a Transformer UP!
| Module:FQ,LS | 2013-06-17 | Mid- and large-sized power transformers need to be able to operate over the long term, so they are always required to control running costs from losses. Iron loss is one of the main losses in a transformer, and it can lead to temperature increases and efficiency decreases because it consumes electric power as heat in a magnetic material.
Using finite element analysis (FEA) to confirm the distribution of iron loss density makes it possible to study a transformer's local geometry during design. Further, iron loss is divided into hysteresis loss caused by hysteresis in the core and joule loss caused by eddy currents, and analysis makes it possible to compare the relative contributions of each of these.
This Application Note presents how to obtain the iron loss and the ratio of hysteresis loss and joule loss within that iron loss for a three-phase transformer.
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 | 116 - Operating Time Analysis of an Injector by Evaluating the Reduction in Eddy Currents UP!
| Module:TR | 2013-06-17 | A solenoid type injector used in engines opens a valve and injects fuel by moving a plunger with magnetic force created by an electromagnet. Injectors in engines need to respond quickly to applied voltage in order to control the amount of fuel flow and improve fuel efficiency.
In solenoid injectors, one of the reasons for slow response is eddy currents, which are produced when the magnetic flux generated by current flow undergoes time variations. The eddy currents are generated in a direction that inhibits changes in the magnetic flux, causing a delay in the initial rise of the attraction force when the current begins to flow. This reduces the injector's responsiveness. JMAG makes it possible to account for effects from eddy currents and obtain an injector's responsiveness by running a transient response analysis. Identifying the places where eddy currents are generated enables a designer to study how responsiveness can be improved.
This Application Note explains how to apply direct current voltage to a solenoid injector and obtain its response characteristics by accounting for effects from eddy currents. The effectiveness of slots added to reduce eddy currents are evaluated by comparing the analysis results with a model without slots added.
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 | 114 - Vibration Analysis of an Outer Rotor Motor
| Module:DP,DS | 2012-07-31 | An outer rotor motor has a magnetic rotor that rotates around a stator. The rotor radius of an outer rotor motor is large, so it can produce a larger amount of drive torque than an inner rotor motor with the same diameter, giving it a superior constant velocity. On the other hand, countermeasures for vibration and noise that occur during rotation are vital as well.
The electromotive force is a cause of the vibration that occurs when a motor rotates. Additionally, when this electromotive force resonates with the motor's eigenmodes, it causes even larger vibrations and noise. Countermeasures such as changing the motor's eigenfrequency through processes like setting a hole in the rotor core have been taken with the objective of preventing resonance. In order to carry out these kinds of studies, it is necessary to get a precise, definite grasp of the electromotive force's spatial distribution, frequency analysis, and natural frequency.
This note presents the use of a magnetic field analysis and structural analysis to obtain the sound pressure caused by electromagnetic vibrations in an outer rotor motor with holes fabricated in the rotor core.
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 | 112 - Starting Thrust Force Analysis of a Linear Induction Motor
| Module:FQ | 2013-04-26 | Linear motors are widely used for carrier devices and machine tools because of their high-speed performance, high acceleration and deceleration, and accurate positioning. One type of linear motor, the linear induction motor, can be constructed at low cost because it can use a primary side with coils, and a secondary side made of a conductor that is not magnetized, such as aluminum or copper.
There are some problems when building a linear inductance motor, such as complex eddy currents flowing in the secondary conductor sheet, and a large amount of leakage flux between the mover and stator. In order to improve linear inductance motor efficiency, therefore, it is important to gain an understanding of the paths of eddy currents and the leakage flux. Evaluation using the finite element method (FEM) is useful for this.
This Application Note presents how to obtain the starting thrust force for a linear inductance motor.
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 | 110 - Loss Analysis of a Choke Coil
| Module:FQ,LS,TS | 2012-07-31 | A choke coil is an electric component that is intended to filter high-frequency current. Measures to evaluate the heat source as well as the core iron losses that occur within the choke coil and the copper losses of the coil that decrease efficiency need to be used for this analysis.
The current generated in the choke coil has offsets caused by the skin effect, proximity effect, and leakage flux near the gap, so it is distributed both inside of and between the wires. Iron loss generated in the core is also distributed by offsets in the core's magnetic flux density. It is helpful to get tips for the design quantitatively and visually studying these detailed distributions, and an effective way of doing this is a magnetic field analysis that uses the finite element method (FEM).
This Application Note shows how to obtain the iron loss and copper loss in a choke coil.
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 | 109 - Operating Time Analysis of an Electromagnetic Relay Accounting for Eddy Currents
| Module:TR | 2013-04-26 | Electromagnetic relays are devices that use an electromagnet to physically connect and disconnect contact points. Magnetic flux is generated from the magnetomotive force, which is expressed as the product of the number of turns in the coil and the current that is applied to the coil. This flux produces an attraction force in the movable core, making the relay close.
To put it simply, the attractive force is determined from the area of the gap between the movable core and the stator core and the size of the magnetic flux density produced in said gap. With a relay whose movable core does not move linearly, however, it is a difficult problem to predict the magnetic flux density in the gap because it does not become parallel. The nonlinear magnetic properties of the iron core and yoke also affect the magnetic flux density in the gap. With a JMAG magnetic field analysis, it is possible to obtain the attraction force of the movable core while accounting for these factors. One of the reasons that the response is delayed in electromagnetic relays is eddy currents, which are produced when the magnetic flux generated by current flow undergoes time variations. The eddy currents are generated in a direction that inhibits changes in the magnetic flux, causing a delay in the initial rise of the attraction force when the current begins to flow. This reduces the injector's responsiveness. JMAG makes it possible to account for the effects from eddy currents and obtain an electromagnetic relay's responsiveness by running a transient response analysis.
This Application Note presents the use of the motion equation function to evaluate the operating time of an electromagnetic relay with DC voltage drive. Eddy currents generated in the core are considered for this purpose.
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 | 108 - Centrifugal Force Rupture Analysis of a Ring Magnet
| Module:DS | 2013-02-28 | As the applications for permanent magnet synchronous motors expand in the manufacturing sector, the development of high-speed-capable motors is continuing apace. One problem during high-speed operation is centrifugal force produced in the rotor, because, in an SPM using ring magnets, a magnet can rupture when the stress acting on it surpasses its mechanical strength. Analyzing the maximum rotation speed of a motor in advance to evaluate methods to prevent the magnet from rupturing, such as designing reinforcing rings, is highly advantageous during the design stage.
When an SPM motor rotates, centrifugal force is generated, producing stress on the magnets. The stress distribution inside the magnets is not uniform. In addition to evaluating their mechanical strength, it is necessary to thoroughly investigate areas of stress concentration using the finite element method (FEM).
This Application Note presents how to obtain the stress distribution of a ring magnet in an SPM motor rotating at high speeds.
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 | 106 - Iron Loss Analysis of a Brush Motor
| Module:DP,LS | 2011-01-17 | Recently, the growing demand for energy conservation and highly efficient motors is raising the importance of reducing losses. Iron loss, which is one of the major losses for motors, is produced when energy is released as heat, causing the efficiency to decrease and the temperature of the motor to rise. It is advantageous to measure the iron losses via simulation during the design stage of a motor.
This example presents the use of a magnetic field analysis to obtain the iron losses of the stator core and rotor core of a brush motor.
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 | 104 - Thrust Force Analysis of a Linear Induction Motor UP!
| Module:DP | 2013-06-17 | Linear motors are widely used for carrier devices and machine tools because of their high-speed performance, high acceleration and deceleration, and accurate positioning. One type of linear motor, the linear induction motor, can be constructed at low cost because it can use a primary side with coils, and a secondary side made of a conductor that is not magnetized, such as aluminum or copper.
Linear induction motors have unique phenomena called end effects that cause reduced performance at low slip, so it is important to grasp thrust force characteristics, including end effects, using magnetic field analysis when evaluating these motors.
This Application Note presents how to obtain thrust force characteristics for a linear inductance motor.
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 | 102 - Magnetic Field Analysis of a Magnetic Sensor
| Module:ST | 2013-02-28 | With recent improvements in the functionality of electric devices and home appliances, magnetic sensors are being used more for contactless sensing of whether device doors, etc. are open or closed. An open/closed switch using a magnetic sensor switches between open and closed by sensing distance according to the size of the magnets' magnetic field. At the design stage, it is necessary to evaluate magnet type and position, sensor sensitivity, and other issues.
Magnetic field analysis simulation using the finite element (FEM) method is effective for accounting for differences in magnetic field strength due to three-dimensional positioning and interference from other magnetic parts.
This Application Note presents how to obtain the magnetic flux density distribution at points in the horizontal and vertical directions away from the magnet.
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 | 101 - AL-Value Current Characteristic Analysis of a Choke Coil
| Module:ST | 2013-04-26 | A choke coil is an electric component that is intended to filter high-frequency current. The AL-value is a vital parameter in a choke coil design that determines the cutoff frequency of a high-frequency current.
Because the AL-value is often set as a design specification and AL-value is a nonlinear magnetic property of the core, it varies widely according to the making current. Finite element analysis (FEA) enables accurate reflection of magnetic properties, and so can obtain AL-value current properties and provide feedback for design.
This note presents the use of a magnetic field analysis to obtain the AL-value current properties of a choke coil.
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 | 100 - Surface Heating Analysis of a Steel Plate
| Module:FQ,HT | 2013-02-28 | High-frequency induction heating is one heating method used when heat treating the surface of a steel plate. With induction heating, the heating depth can be adjusted because it is possible to localize heating by modifying the coil's geometry and electrical power. The coil geometry, heating conditions, etc. must be designed correctly in order to achieve heating as desired, but the cost and time needed for prototyping can be a problem.
To make accurate predictions, it is necessary to account for the temperature dependency of the thermal conductivity, the electrical conductivity, and the detailed coil geometry in order to find the heat generation distribution. Electromagnetic field simulation using the finite element method (FEM) is needed for this type of prediction.
This Application Note presents how to confirm the uniformity of the surface temperature distribution in the steel plate facing the coil and check for an eddy current distribution that causes the temperature distribution to be uneven, when a mosquito-coil-shaped coil is in position.
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 | 99 - Superimposed Direct Current Characteristic Analysis of a High Current Reactor UP!
| Module:TR | 2013-06-17 | High-frequency, high-current reactors have a current composed of direct current with high-frequency ripple superimposed on it. In terms of reactor performance, stable inductance over a wide range of direct current is desirable. Also, the gap installed to prevent magnetic saturation in the core has a large effect on the inductance, and thus is a vital parameter in reactor design.
Finite element method (FEM) analysis is useful for accurately estimating inductance over a wide current range, while also accounting for the effects of the gap's inductance and nonlinearity in magnetization properties, and applying this during design.
This Application Note presents how to obtain a high-current reactor's superimposed direct current characteristics when the gap length is varied.
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 | 97 - Sound Pressure Analysis of a Transformer UP!
| Module:DS,FQ | 2013-06-17 | In recent years, the demand to reduce vibration and noise is growing while the requirements for higher efficiency and smaller and lighter transformers grow with environmental conservation trends. The primary cause of noise for transformers is the electromagnetic vibrations and the resonance phenomena at the eigenfrequency of the structure. A sound pressure analysis can be performed with a coupled magnetic field and structural analysis that uses the electromagnetic force as excitation force.
This example presents the use of a coupled magnetic field and structural analysis to obtain the sound pressure distribution accounting for the electromagnetic force of the core when the transformer is operating on a power supply frequency of 6 kHz.
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 | 95 - Analysis of Characteristics of a Universal Motor
| Module:DP | 2012-03-01 | Universal motors rotate by either AD or DC. Since universal motors have a simple structure which is robust, compact, and capable of high speeds, they are used in home appliances and industrial electric tools.
Also, in universal motors, the rotation speed is determined by the load when field coil and armature coil are connected in series.
This note presents the use of magnetic field analysis to obtain the characteristics of the universal motor, including torque versus current (T-I), torque versus speed (T-N), and magnetic flux density distribution.
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 | 91 - Iron Loss Analysis of an IPM Motor Including the Effects of the Press Fitting Stress
| Module:DP,DS,LS | 2013-02-28 | One of the demands for IPM motors is higher efficiency over a wide range of rotation speeds in combination with motor drives, as reluctance torque can be used in addition to magnet torque. Iron loss makes up a particularly large proportion of total loss in the high rotation region, and how to make this smaller is a major design issue. Generally, IPM motor cores have laminated structures, and methods such as press fitting or shrink fitting are used to maintain them.
For motors using magnetic steel sheet for their cores, the stress generated by press fitting can increase iron loss, so it is important to take this stress into account when evaluating iron loss.
Iron loss is generated when there are magnetic-field variations in steel sheet. Also, the amount of iron loss depends on the steel sheet's iron loss properties. These iron loss properties of steel sheet become worse when it is subjected to stresses such as press fitting. The stress caused by press fitting has its own distribution, and is particularly large in the back yoke. So, in order to evaluate the iron loss with good accuracy, it is necessary to correctly obtain the stress distribution for the magnetic flux, time variation, and steel sheet.
This Application Note presents modeling the press fitting of a core and frame with the Press Fit condition and then obtaining the iron loss density of an IPM motor with and without accounting for the stress generated at that time.
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 | 90 - Analysis of the Effect of PWM on the Iron Loss of an IPM Motor
| Module:DP,LS | 2012-07-31 | Current vector controls are generally used in interior permanent magnet synchronous motors (hereinafter referred to as IPMs), and among them PWM inverters are widely utilized to create a command current. It is vital to get a good understanding of iron losses in order to raise the efficiency of an IPM motor. However, iron losses increase when power is converted by the PWM inverter because the carrier harmonic created by the PWM becomes superimposed on the current and the magnetic flux density waveform in the IPM motor's core.
There are two methods for obtaining iron loss that considers the PWM's carrier harmonics: Couple a control/circuit simulator that contains the PWM inverter with a magnetic field analysis by inputting the current waveform obtained from the simulation into the analysis, or input the actual measurements of a current into a magnetic field analysis.
This Application Note demonstrates an analysis in which a coupled analysis between a separate JMAG-RT model and a control/circuit simulator is carried out, and the effects of a carrier harmonic against an IPM motor's iron loss are displayed by inputting the current waveform calculated from the analysis.
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 | 89 - Stiffness Torque Analysis of a PM Stepper Motor
| Module:TR | 2013-02-28 | PM stepper motors are commonly used for positioning of moving parts in small devices such as printers and video equipment. In order for its drive to function with an open loop, the most important characteristics for a stepper motor are controllability and holding torque, and not the motor's output. Therefore, the desired characteristics are detent torque, which is a non-excitation holding torque, and stiffness torque, which is an excitation holding torque.
A PM stepper motor is made up of a multi-pole magnetized rotor and offset inductors for each phase. In order to reduce their size and number of parts, claw pole inductors are made from folded steel sheet. Because of this, the flow of magnetic flux is three dimensional, so it is necessary to carry out a 3D electromagnetic field analysis using the finite element method (FEM) to proceed with an accurate preliminary study.
This Application Note describes how the stiffness torque at 0.5 A of current can be calculated for a PM stepper motor.
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 | 87 - Iron Loss Analysis of an IPM Motor Including the Effect of Shrink Fitting
| Module:DP,DS,LS | 2013-02-28 | Magnetic steel sheet is used for the cores of drive motors for HEVs and EVs. This is to make them more compact, lighter, and more efficient. The main point for improving efficiency in an IPM motor's high rotation speed region is how to reduce iron loss. However, shrink fitting is used in order to strengthen the joint between frames and stator cores with laminated structure. The compressive stress generated during shrink fitting is known to increase iron loss. Therefore, it is important to account for the effects of this stress when evaluating iron loss.
Iron loss is generated when there are magnetic-field variations in steel sheet. Also, the amount of iron loss depends on the steel sheet's iron loss properties. These iron loss properties of steel sheet become worse when it is subjected to stresses such as shrink fitting. The stress caused by shrink fitting has its own distribution, and is particularly large in the back yoke. So, in order to evaluate the iron loss with good accuracy, it is necessary to correctly obtain the stress distribution for the magnetic flux, time variation, and steel sheet.
This Application Note presents how to obtain the iron loss density of an IPM motor with and without accounting for this stress.
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 | 85 - High-Frequency Induction Heating Analysis of a Constant Velocity Joint | Module:FQ,HT | 2012-11-14 | Constant velocity joints are used in the connections at each end of a drive shaft in a vehicular drive system. The inside of the outer race of a constant velocity joint makes direct contact with steel balls or rollers on the inner race, so it needs to have increased hardness to improve its ability to resist wear and tear. On the other hand, its inside needs to retain its toughness in order to maintain its flexibility as a part. High-frequency induction hardening is used as a heat treatment method that hardens only the surface of a product. With this method, using a high-frequency power supply makes it possible to heat the surface locally and rapidly. This process also has many other benefits, such as providing a clean working environment because it uses electrical equipment, being very efficient, and providing uniform results for each product. This is why it is being aggressively implemented in the field. It is difficult to predict the hardening of the inside of a constant velocity joint because its uneven geometry makes eddy currents and magnetic flux flow in a complex manner.
With interior hardening like the kind used in this example, the heating coil design must follow spatial constraints. The eddy currents that are generated from a high-frequency varying magnetic field are offset on the surface of the part's interior, so the material properties change a great deal as the temperature rises. This is why it is necessary to predict the amount of heat generated in a numerical analysis based on the finite element method (FEM) in order to handle the detailed phenomena.
This Application Note shows how to run an analysis of the elevated temperature process by using the geometry of a coil to evaluate whether or not the target temperature conditions are fulfilled.
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 | 84 - Electromagnetic Forming Analysis of a Tube
| Module:DP | 2013-01-28 | Electromagnetic forming is a process in which eddy currents are generated in a tube when a large, instantaneous current is run through a coil, creating a strong magnetic field. The tube is formed by using the Lorentz force produced by the interaction between these magnetic fields. This method is different from forming that uses plastic deformation with a press mold because it deforms with the power of the tube itself. This makes it possible to perform difficult forming, like with an object that will not fit into a normal press mold. However, the force generated in the tube is determined from induced eddy currents, which means that it is dynamic deformation, so the behavior of its deformation is known for being difficult to analyze.
Using JMAG to properly analyze the Lorentz force distribution generated in the tube can assist with predicting the deformation behavior of the electromagnetic forming process.
This Application Note explains how to obtain the Lorentz force density distribution generated in a tube when current is run through a coil.
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 | 83 - Magnetic Shielding Analysis of an Induction Furnace
| Module:FQ | 2013-02-28 | An induction furnace is an apparatus that uses high-frequency induction heating to melt metal. Running current through the coil surrounding the crucible starts electromagnetic induction phenomena, which generate current in the metal in the crucible. This current produces joule losses in the metal, which are used to heat and melt it. Magnetic yokes are arranged around the coil. The yokes are used as strong components that prevent the Lorentz force generated by the coil from damaging and deforming it. The magnetic yokes also reduce the leakage flux that flows out of the appliance, preventing unintended heating in surrounding structures. Keeping the amount of material used in the magnetic yokes to a minimum makes it possible to reduce the cost of the apparatus.
To understand the magnetic flux that spreads from the induction furnace, it is necessary to use the eddy current distribution and magnetic flux flow in the metal in the crucible, as well as the concentrations in magnetic flux caused by the positions of the yokes.
This Application Note displays magnetic flux density distribution to evaluate the differences in magnetic flux with and without yokes.
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 | 82 - Analysis of a Synchronous Reluctance Motor
| Module:DP | 2013-01-28 | Skyrocketing prices of rare earth magnets have led to rising expectations for synchronous reluctance motors (referred to below as SynRMs), which do not use permanent magnets. SynRMs have a simple structure that can achieve solid performance at a low price. However, torque is generated only by the rotor's saliency and the coil's magnetomotive force, so raising the torque density depends greatly on the core's nonlinear magnetic properties and the rotor geometry. This is why they have a different format than a typical motor. On the other hand, the aforementioned rising prices of rare earth magnets, improvements in current control technology, and the ability of optimization designs using magnetic field analysis have raised the possibility of lowering these barriers, giving SynRMs the chance to be reexamined.
SynRMs operate using the nonlinear region of a magnetic steel sheet, so the inductance expresses nonlinear behavior as well. This behavior distorts the excitation current waveform a great deal, making it impossible to run advanced projections that are accurate with calculation methods that follow linear formulas. Consequently, it becomes necessary to use the finite element method (FEM), which can handle nonlinear magnetic properties in material, detailed motor geometry, and transient currents.
This Application Note presents an evaluation of torque variations that occur when the phase of a sinusoidal wave current is changed.
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 | 80 - Cogging Torque Analysis of an SPM Motor with Skewed Magnetization
| Module:TR | 2013-02-28 | Reductions in vibration and noise are being sought after because they are a cause of torque variations in motors, and demands for reduction are particularly strong with motors that are used in machine tools and power steering. Cogging torque, which is a torque variation that is produced when there is no current, is generated because the electromagnetic force produced in the gap changes according to the rotor's rotation. This makes it necessary to apply skew to the stator and rotor and come up with innovative geometry for the magnet and stator in order to reduce torque variations by limiting variations in the electromagnetic force. Applying skew reduces the cogging torque, but it also brings disadvantages such as producing force in the thrust direction and generating eddy currents from the magnetic flux that links in the lamination direction.
Consequently, in order to accurately evaluate a motor that has skew applied, one needs a magnetic field analysis simulation that uses the finite element method (FEM), which can account for a detailed 3D geometry, instead of studies that use the magnetic circuit method or a 2D magnetic field analysis.
This Application Note presents the use of a magnetic field analysis to obtain the flux density distribution, cogging torque, and induced voltage of an SPM motor that has skewed magnetization applied to its magnet.
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 | 78 - Loss Analysis of a Sheet Coil Transformer
| Module:FQ,LS | 2013-01-28 | Power transformers need to be able to operate over the long term, so they are always required to control running costs from losses. Iron loss is one of the main losses in a transformer, and it can lead to temperature increases and efficiency decreases because it consumes electric power as heat in a magnetic material.
Using a finite element analysis (FEA) to display the iron loss density distribution and obtain the iron loss values in a transformer makes it possible to study the local geometry and get design feedback at the design stage.
This Application Note shows how to obtain the iron loss of a sheet coil transformer.
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 | 77 - Inductance Analysis of an RFID Tag
| Module:FQ | 2013-04-26 | An RFID tag uses electromagnetic induction to communicate information by supplying electrical power to an IC chip from a reading device. In order to relay information in specific frequencies with a good degree of sensitivity, the RFID tag uses resonance between its internal coil antenna and capacitor.
The coil antenna's inductance and the capacitor's resonance frequency need to be estimated for resonance to be produced accurately at the specified frequency. When the capacitor is external, the inductance of the coil antenna needs to be obtained accurately and the capacitor's capacity needs to be identified. Some RFID tags have magnetic sheets or metallic films on them. The sheet's magnetic properties and eddy currents generated in the film can affect the inductance.
This Application Note performs a magnetic field analysis of an RFID tag that has a metallic film and a magnetic sheet with a resonance frequency of 13.56 MHz, and obtains the magnetic field distribution and the RFID tag's inductance.
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 | 75 - Iron Loss Analysis of a Reactor
| Module:FQ,LS | 2013-01-28 | Reactors are installed on the input or output side of inverter circuits. Because they are required for long-term operation, the ability to control running costs from losses is an important challenge for their design. Iron loss is one of the major types of losses in a reactor. It consumes electric power as heat in a magnetic body, so it causes heat to increase and efficiency to decrease in the reactor.
Using a finite element analysis (FEA) to confirm the distribution of iron loss density makes it possible to study a reactor's local geometry during its design, so it is useful in providing feedback about the design itself.
This Application Note analyzes the iron loss of a reactor.
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 | 74 - Speed Versus Torque Analysis of a Single-Phase Induction Motor | Module:DP | 2012-08-31 | Single-phase induction motors are widely used as small output motors for the drives in household electrical appliances and office machinery, like fans and washing machines, because they can use single-phase AC, the typical power source for home electronics. Unlike three-phase AC, however, single-phase AC cannot create a rotating magnetic field by itself, meaning that it cannot start a motor. For this reason, it needs to use an alternate method to generate a rotating magnetic field to start the motor.
The induced current flowing in the secondary conductor largely affect the performance of the motor because the motor rotates by using the interaction between this current and the magnetic field of the stator coils. Strong magnetic saturation distribution is also generated near the gap, so the nonlinear characteristics of the magnetic properties have a big influence on performance, as well. At the step before the design phase, it is helpful to run an analysis and evaluation using the finite element method (FEM) to understand a single-phase induction motor's characteristics by accounting for induced current and magnetic saturation characteristics.
This Application Note explains how to obtain the current density distribution and Speed-Torque curve created by auxiliary winding that uses a capacitor.
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 | 73 - Analysis of Capacitance of a Parallel Plate Capacitor
| Module:EL | 2013-01-28 | Capacitors are widely used as basic passive components in a variety of electric circuits. Parallel plate capacitors are taken up as the subject matter for how to obtain capacitance, a basic electric property, because they follow simple phenomena. Two electrode plates are placed in the air to face each other. When a constant electric potential difference is applied to them, they store an electric charge. The capacity of the charge stored in the electrode plates changes depending on the permittivity of the dielectric material between them.
This Application Note explains how to use JMAG to calculate the capacitance when the dielectric material is air and when it is a high permittivity material, while obtaining the amount of charge in each.
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 | 72 - Analysis of Attractive Force between Steel Plates and a Magnet
| Module:ST | 2013-04-26 | Many electronic products that have movers use the attractive force generated between magnets and magnetic materials. Even magnetic materials that are not magnetized themselves take on magnetic properties when in the vicinity of a magnet, generating an attractive force between the two bodies.
In order to understand the phenomena where the magnet and magnetic material attract each other, it is helpful to visualize the magnetic flux flowing through the air. Using a magnetic field analysis makes it easy to visualize and understand these phenomena.
This Application Note explains how to obtain the magnetic flux density distribution and attractive force generated between a steel plate and a magnet.
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 | 71 - Basic Characteristic Analysis of a Motor with 2 Brushes, 6 Poles, and 19 Slots
| Module:DP | 2013-04-26 | Small brush motors generally have a structure containing 2 poles and 3 slots, but there are times when a multi-pole structure is adopted in order to produce higher torque. The reason for this is because achieving a higher torque makes it possible to omit deceleration systems. Brush motors have a construction where the number of poles and number of slots are not divisible, with the objective of raising the rectification effect or limiting torque variations. In exchange for reducing torque variations, however, there is a drawback when it comes to torque output. This is why selecting the number of poles and slots have become a design theme, especially when it comes to small motors, which have a small number of slots. This makes the selection process difficult because the difference in distribution becomes large. The model for this analysis has 6 poles and 19 slots, so there are 3.16 slots per pole. They cannot be divided into decimals however, so there have to be either 3 or 4 slots for each magnetic pole. As a result, the induced voltage in each coil and the torque generated are unbalanced.
These evaluations need to be able to account for an accurate circuit geometry, and the current flowing through coil connected via a commutator needs to be handled accurately, as well. This is why an electromagnetic field analysis using the finite element method (FEM) is necessary to account for everything.
This Application Note presents an analysis to obtain the speed versus torque and torque versus current for a motor that has 2 brushes, 6 poles, and 19 slots.
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 | 70 - Analysis of Impedance-Frequency Characteristics of a Cable
| Module:FQ | 2013-04-26 | Twisted pair cables are used in situations that require strict noise reduction like with signal lines and speaker cables because they are not affected by external noise and do not emit much noise of their own. The cable's performance relies on its electric properties, but these change depending on the state of the current that is flowing. For example, when the current frequency rises, the current is offset in the copper wires because of the skin effect and proximity effect. As a result, the apparent cross-sectional area of the current flow is reduced, causing the alternating current resistance to increase and the inductance to change. An increase in the resistance leads to an increase in losses, and changes in inductance result in distortions in the signal. This is why these frequency characteristics need to be understood in advance.
The above phenomena occur in the interior of the copper wires, so an evaluation using a magnetic field analysis based on the finite element method (FEM) is useful because they can be difficult to predict with manual calculations.
This Application Note explains how to obtain the frequency characteristics of the resistance and inductance in twisted pair cables.
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 | 69 - Iron Loss Analysis of an IPM Motor UP!
| Module:DP,LS | 2013-06-17 | Demand for higher efficiency and smaller size in motors has grown from the need to accommodate devices that incorporate miniaturization and energy efficiency in their designs. In order to meet this demand, motors have to improve their output density and reduce their losses. One type of loss commonly found in motors is iron loss, which increases drastically at high rotation speeds and high magnetic flux densities. This increase can lead to a rise in temperature and a reduction in efficiency. Consequently, it is growing more important to predict iron loss levels at the motor design stage.
Unfortunately, it is not possible to obtain iron losses accurately in studies that use the magnetic circuit method or rules of thumb. In order to obtain them accurately, one needs to find the distribution and time variations of the magnetic flux density in each part of the motor after accounting for a fine geometry and the material's nonlinear magnetic properties. Using the finite element method (FEM) is essential in order to carry out this kind of a detailed analysis.
This Application Note explains a case example that obtains the iron loss and its distribution in a permanent magnet motor.
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 | 68 - Speed Versus Torque Characteristic Analysis of a Three-Phase Induction Motor
| Module:DP | 2013-02-28 | An induction motor is a motor in which a rotating magnetic field in the stator coils causes induced current to flow in an auxiliary conductor. This current and magnetic field exert force on the auxiliary conductor in the rotation direction and cause the motor's rotor to rotate. Induction motors are widely used in everything from industrial machines to home appliances because they have a simple construction and are small, light, affordable, and maintenance-free.
In an induction motor, the current induced by the auxiliary conductor exerts a large influence on its characteristics. It also causes strong magnetic saturation in the vicinity of the gap, in particular. This is why a magnetic field analysis based on the finite element method (FEM) is useful when investigating the motor's characteristics for a design study.
This Application Note explains an analysis that confirms the Speed-Torque curve and current density distribution of an induction motor.
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 | 66 - Operating Time Analysis of an Injector
| Module:DP | 2012-07-31 | A solenoid type injector used in engines opens a valve and injects fuel by moving a plunger with magnetic force created by an electromagnet. Injectors in engines need to respond quickly for applied voltage to improve fuel consumption by maintaining the amount of fuel flow.
In solenoid injectors, one of the reasons that the response is delayed is eddy currents, which are produced when the magnetic flux generated by current flow undergoes time variations. The eddy currents are generated in a direction that inhibits changes in the magnetic flux, causing a delay in the initial rise of the attraction force when the current begins to flow. This reduces the injector's responsiveness. JMAG makes it possible to account for the effects from eddy currents and obtain an injector's responsiveness by running a transient response analysis. Identifying the places where eddy currents are generated enables a designer to study whether or not responsiveness can be improved.
This Application Note explains how to apply direct current voltage to a solenoid injector and obtain its response characteristics by accounting for effects from eddy currents.
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 | 65 - Static Thrust Analysis of a Voice Coil Motor
| Module:TR | 2013-01-28 | Linear actuators are used in machine tools because of their high-speed performance, high acceleration and deceleration, and accurate positioning. There are coreless types of linear actuators, as well. They generally have a smaller thrust force than core linear actuators, but they do not produce cogging, so they only have a small amount of thrust variation. Because of this property, they are used in fields where high-accuracy positioning is necessary, like with head drives of packaging machines or the slight movements of precision stages.
Static thrust variations at the translation position of the actuator have an effect on determining the position accurately. The static thrust is determined by the amount of current, so its current characteristics need to be obtained.
This Application Note explains how to obtain the current characteristics and the translation position characteristics of the static thrust in a voice coil motor, which is a type of coreless linear actuator.
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 | 63 - Analysis of Torque Characteristics of a Cage Induction Motor
| Module:FQ | 2013-02-28 | Induction motors have been widely used for a long time in general industries because they have a simple structure, and are affordable, robust and highly efficient. When an induction motor rotates at synchronous speed, no torque is produced. However, when proper slip is caused, the maximum torque can be obtained. Losses are generated in a cage induction motor when current flows through the cage, so the pros and cons of continuous rotation depending on the amount of the heat generated need to be studied.
In an induction motor, the current induced by the auxiliary conductor exerts a large influence on its characteristics. It also causes strong magnetic saturation in the vicinity of the gap, in particular. This is why a magnetic field analysis based on the finite element method (FEM) is useful when investigating the motor's characteristics for a design study.
This Application Note introduces a case example that obtains the Slip-Torque curve, Torque-Current curve, Current-Voltage curve at maximum torque, and the Current-Joule Loss curve for the cage.
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 | 62 - Attractive Force Analysis of a Solenoid Valve
| Module:DP | 2013-01-28 | Solenoid valves move their iron cores in a translational direction, and are used to adjust the inflow and outflow amounts of liquids and gasses. Running current through the coil forms an electromagnet, which generates an electromagnetic attraction force between the mover and stator. A high level of responsiveness is required to open and close the valve, so the power supply and valve used in the drive need to be evaluated to determine whether they fulfill the required responsiveness and attraction force.
The attraction force is determined from the size of the current, the arrangement of the iron core, and the material properties, but the actual magnetic flux flow is complex. Even if the current is increased, there are times when the attraction force does not increase correspondingly in the vicinity of the iron core's magnetic saturation region. A magnetic field analysis simulation using the finite element method (FEM) is useful in studying these kinds of behaviors.
This Application Note obtains the attraction force at each position of the movable core.
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 | 61 - Current Distribution Analysis of a Choke Coil
| Module:DP,TS | 2013-01-28 | A choke coil is an electric component that is intended to filter high-frequency current.
The current in a choke coil's interior produces local heat generation because of the skin effect, proximity effect, and current offsets caused by leakage flux near the gap. From a heat resistant design standpoint, visual confirmation of detailed current distribution using a finite element analysis (FEA) is useful because it provides feedback for the design.
This Application Note explains a case example that obtains the current distribution in a choke coil.
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 | 60 - Superimposed Direct Current Characteristic Analysis of a Reactor
| Module:TR | 2013-04-26 | A high-frequency reactor, used in equipment such as DC-DC converters, has a high-frequency current accompanying the switching direct current. The performance of a reactor is evaluated by a stable inductance in a wide direct current region. The gap that is designed to prevent magnetic saturation from the core largely affects the inductance, so it is a vital parameter of the reactor's design.
The magnetic resistance is determined by the gap when there is a large gap width, which is used as a parameter for the superimposed direct current of the inductance. This means that the resistance can be evaluated using the magnetic circuit method, but when the gap width is small, the current is large, and magnetic saturation has a large effect on the inductance, an advance study using a finite element analysis (FEA) is an effective tool.
This Application Note explains a case example that obtains the superimposed direct current characteristics of a high-frequency reactor when the gap width is changed.
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 | 59 - Iron Loss Analysis of an IPM Motor Accounting for a PWM -Direct Link- | Module:DP,LS | 2012-08-31 | Vector controls using a PWM (Pulse Width Modulation) control are commonly included in the drive circuits of high efficiency motors. A PWM control makes it possible to adjust the phase or amplitude of a current according to load and rotation speed, so they can achieve high efficiency in a wide operation range. The control frequency of a PWM is called a carrier frequency. Carrier frequencies are often used up to almost 20 kHz. To form the current waveform supplied by the PWM control, the carrier harmonic current is superimposed on the basic wave current. This carrier harmonic current applies a high-frequency magnetic field to each part of the motor. As a result, core iron loss and magnet eddy current loss are generated.
The total amount of these losses is not a dominant factor, but they can be a hindrance when trying to raise efficiency, so they need to be eliminated in the design process. In order to study these problems, both the motor's electromagnetic behavior and what kinds of controls the drive circuit performs have to be investigated.
In order to run an advance study of these phenomena in CAE, a high fidelity motor model and inverter model need to be coupled. There are three ways of accomplishing this: Directly linking with a circuit/control simulator, entering a current waveform obtained by using a JMAG-RT motor model and a circuit/control simulator, and entering actual current measurements.
In this analysis, the iron losses of the IPM motor that accounts for the carrier harmonic are obtained by directly linking to a circuit/control simulator.
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 | 58 - Efficiency Analysis of an IPM Motor
| Module:DP,LS | 2013-01-28 | An IPM motor's features are in its rotor geometry, where its magnets are embedded. When the stator's rotating magnetic field is applied in a direction that runs perpendicular to the rotor magnets (the q-axis) the motor operates like a normal SPM motor. When the current phase is displaced and the d-axis component is applied, however, the motor operates so that the magnetic fields in the rotor magnets are weakened. This is called field weakening. In an SPM motor the d-axis current operates enough to weaken the magnetic field, so the rotation speed increases but the torque decreases. However, the rotor geometry in an IPM motor is created so that there is a difference in inductance between the d-axis and q-axis, so it is possible to generate torque with the d-axis current, which weakens the magnets. This makes it possible to recover the part weakened by the flux. Consequently, an IPM motor achieves a greater range of operation by incorporating field weakening controls.
For this reason an IPM motor's characteristics depend greatly on its rotor geometry, so studies using the magnetic circuit method are difficult. In order to perform an advance design study accurately, an electromagnetic field analysis using the finite element method is necessary.
This Application Note presents the use of magnetic field analysis to obtain the efficiency of an IPM motor in each current phase with a rotation speed of 1800 rpm and the current amplitude of 4.0 A when the motor is driven by sinusoidal wave current.
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 | 56 - Torque Characteristics Analysis of a Self Starting Type Permanent Magnet Motor
| Module:DP | 2013-04-26 | A self starting permanent magnet motor combines the characteristics of an induction motor and a permanent magnet motor, so it has higher efficiency than an induction motor even without a control device like an inverter. It behaves as an induction motor when it starts, generating torque when the rotor cage first slips against the rotating magnetic field created by the stator and then produces a secondary current. Consequently, this kind of motor has superior starting ability because there is no need to account for the rotor's start-up position or rotation speed. When the rotation speed increases and the motor synchronizes, the permanent magnet begins to generate the magnetomotive force and produce torque instead of the secondary current, so there is no secondary iron loss. This kind of motor has a weak point, however: The torque falls a great deal when the motor deviates from its synchronicity, and it gets out of step as a magnet motor so the torque variations are large. This is why self starting permanent magnet motors can achieve full-voltage starting with household current and are very efficient while in a synchronous state, but have drawbacks like relatively low starting torque and recovery once they have lost synchronization.
These factors make it so that a magnetic field analysis simulation based on the finite element method is necessary to investigate whether the motor's characteristics meet the requirements ahead of time.
This Application Note shows how to obtain the current density distribution and slip versus torque curve.
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 | 54 - Analysis of the Cogging Force of a Moving Coil Linear Motor
| Module:TR | 2013-04-26 | Linear motors have been widely used in carrier devices and the drive units of machine tools due to their capability for high acceleration and deceleration, as well as their accurate positioning. In order to improve performance people are trying to obtain a large thrust force in order to enhance responsiveness, but one also needs to fulfill the demand for the trade-off of reducing thrust force variations and the attraction force. There are also times when skew is added to the magnets because of requirements to reduce thrust force variation.
In order to obtain a large thrust force, the material's nonlinear magnetic properties and the magnet's demagnetization characteristics need to be accounted for, and they need to be analyzed after modeling a detailed geometry in order to evaluate thrust force variations. This is why the characteristics need to be studied with a magnetic field analysis simulation based on the finite element method (FEM).
This Analysis Note explains how to obtain the magnetic flux density distribution and cogging in a moving coil linear motor with skew applied to its magnets.
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 | 53 - Magnetic Shielding Analysis of a Shield Room
| Module:FQ | 2013-01-28 | Shield rooms are meant to protect precision equipment from the influence of external magnetic fields, so they have to be an enclosed space that implements special processing in the walls that blocks magnetic flux. The effects of external magnetic fields inside the shield room depend on how they are generated, where the precision equipment is located, and the position of the shield room's opening and supply cable.
A magnetic field analysis using the finite element method is necessary to perform an evaluation that deals with three dimensional and temporal variations to figure out how magnetic flux enters the shield room when several external magnetic fields have been applied.
This Application Note explains how to handle the magnetic shielding phenomena used by the shield room when an external magnetic field is applied, and from there how to confirm the magnetic flux density distribution.
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 | 52 - Inductance Analysis of a Sheet Coil Transformer
| Module:FQ | 2013-02-28 | Power transformer requires large currents, so their geometry tends to be large. This means that they are particularly hard parts to miniaturize when electrical product designs get smaller. The sheet coil transformer introduced in this Application Note achieves thinner dimensions by winding its coil in a thin sheet.
Self-inductance and leakage inductance are critical items in a transformer's design requirements. The amount of inductance is dependent on the magnetic circuit, but the nonlinear characteristics of the magnetic properties make it so that the magnetic circuit changes when the operating point changes. The leakage inductance has all of the same properties, but it also has a flux path in non-magnetic regions, making it easily affected by the geometry and coil arrangement in addition to the core. This is why a magnetic field analysis using the finite element method (FEM) is necessary when evaluating these types of inductance.
This Application Note explains how to obtain the self-inductance and leakage inductance of a sheet coil transformer.
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 | 51 - High-Frequency Induction Heating Analysis of a Gear
| Module:FQ,HT | 2013-01-28 | Gears are created in such a way that the surfaces of their teeth are hard in order to resist the wear and tear that occurs when they come into contact with the teeth of other gears. However, this has to be accomplished while maintaining the gear's overall toughness. By using high-frequency induction heating, which is a type of surface hardening method, the teeth are heated rapidly on only their surface by a high frequency power source. This process also has many other benefits, such as providing a clean working environment because it uses electrical equipment, being very efficient, and providing uniform results for each product. This is why it is being aggressively implemented in the field. On the other hand, there are several factors that need to be studied in order to heat the gear's surface uniformly, such as how to adjust the heating coil's geometry, arrangement, current frequency and size.
The eddy currents generated by high-frequency varying magnetic fields are uneven in the tooth surface, so the material properties change a great deal as the temperature rises. In order to handle the detailed phenomena, it is necessary to calculate the heat generation amount in a numerical analysis based on the finite element method (FEM).
This Application Note shows how to create a numerical analysis model when obtaining the optimum coil geometry and current conditions (power supply frequency and current value), analyze the elevated temperature process, and evaluate whether or not the model fulfills the target temperature distribution.
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 | 50 - High-Frequency Induction Heating Analysis of a Steel Wire (Translational Induction Hardening)
| Module:FQ,HT | 2012-07-31 | Steel wires are made to be resistant to wear and tear. This is accomplished by giving them a certain degree of flexibility by maintaining their inner toughness while increasing the hardness of their surfaces. By using high-frequency induction heating, which is a type of surface hardening method, the steel wire is heated rapidly on only its surface by a high frequency power source. This process also has many other benefits, such as providing a clean working environment because it uses electrical equipment, being very efficient, and providing uniform results for each product. This is why it is being aggressively implemented in the field. On the other hand, when the heating target is a long steel wire, it is heated rapidly while passing through the heating coil. For this reason, there are several factors that need to be studied when assigning a heating amount to correspond to the speed at which the wire passes through the coil. Examples of these are: the arrangement of the heating coils so that it can fulfill the necessary heating amount, and how to adjust the current's frequency and size.
This Application Note presents a simulation of the heating conditions of a sufficiently long steel wire that passes through a heating coil. The eddy currents produced from the high frequency's varying magnetic fields are uneven on the steel wire's surface, so its material properties change due to increases in temperature. This is why it is necessary to approximate the amount of heat generated in a numerical analysis based on the finite element method (FEM) in order to handle the detailed phenomena.
This Application Note explains how to create a numerical analysis model when obtaining the optimum coil geometry, current conditions (power supply frequency, current value), and movement speed. It also shows how to evaluate whether the model fulfills the target heating speed by analyzing the elevated temperature process.
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 | 49 - High-Frequency Induction Heating Analysis of a Steel Sheet | Module:FQ,HT | 2012-08-31 | The rolling process of steel sheets changes the strength and properties of the product, so heat treatment is used. High frequency induction heating is a type of heat treatment that uses a high frequency power source to produce rapid heating, allowing the equipment on the production line to be smaller. It also has a multitude of benefits, such as being highly efficient and providing a clean working environment. When the object being heated is a long steel sheet, this process heats it quickly while sending it through a heating coil. For this reason, there are several factors that need to be studied when assigning a heating amount to correspond to the speed at which the sheet passes through the coil. Examples of these are: the arrangement of the heating coil so that it can fulfill the necessary heating amount, and how to adjust the current's frequency and size.
This Application Note presents a simulation of the heating conditions of a sufficiently long steel sheet that passes through a heating coil. The eddy currents produced from the high frequency's varying magnetic fields are uneven on the steel sheet's surface, so its material properties change due to increases in temperature. This is why it is necessary to approximate the amount of heat generated in a numerical analysis based on the finite element method (FEM) in order to handle the detailed phenomena.
This Application Note explains how to create a numerical analysis model when obtaining the optimum coil geometry, current conditions (power supply frequency, current value), and movement speed. It also shows how to evaluate whether the model fulfills the target heating speed by analyzing the elevated temperature process.
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 | 48 - High-Frequency Induction Heating Analysis of a Printer Roller
| Module:FQ,HT | 2013-01-28 | A printer works by running a piece of paper with toner on it between a heated fuser roller and a pressure roller. The heated fuser roller then applies heat to fix the toner to the paper. The fuser roller needs to have uniform temperature distribution in order to handle various types of paper. It also requires the ability to heat up rapidly in order to shorten the standby time, allowing the person using the printer to print documents quickly.
A magnetic field analysis using the finite element method (FEM) is useful in examining several aspects of the process, including: Differences in heating from the heating coil's geometry or placement, what kind of eddy currents are generated in the roller's thin surface and whether they provide uniform temperature, and how the magnetic flux flow spreads to the roller, air, and core.
This Application Note confirms the non-uniformity in temperature distribution produced by an assumed coil geometry, as well as the temperature elevation in each part caused by rotation.
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 | 47 - High-Frequency Induction Heating Analysis of a Crankshaft
| Module:FQ,HT | 2012-07-31 | Machine parts like shafts and gears are made to be resistant to wear and tear. This is accomplished by giving them a certain degree of flexibility by maintaining their interior toughness while increasing the hardness of their surfaces. By using high-frequency induction heating, which is a type of surface hardening method, the part is heated rapidly on only its surface by a high frequency power source. This process also has many other benefits, such as providing a clean working environment because it uses electrical equipment, being very efficient, and providing uniform results for each product. This is why it is being aggressively implemented in the field.
With induction hardening like the kind used on the work piece in this analysis, the main requirement is to heat a given surface uniformly and increase rigidity. Eddy currents generated by the high-frequency varying magnetic field occur in the surface of the work piece. Examining these phenomena in detail requires handling the phenomena that occur in the work piece itself in a numerical analysis based on the finite element method (FEM).
This Application Note shows an example of an evaluation performed by creating a numerical analysis model, analyzing the elevated temperature process, and seeing whether or not the desired temperature distribution is achieved.
Use this analysis when obtaining the optimum coil geometry, current conditions (power supply frequency, current value), and rotation speed.
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 | 45 - High-Frequency Induction Heating Analysis of an IH Cooking Heater
| Module:FQ,HT | 2013-02-28 | An IH cooking heater cooks food by heating a pot that acts as a conductive body. It heats this pot with an induction heating method that uses electromagnetic induction. Eddy currents flow in the iron pot when a high frequency current is applied to the coil. These eddy currents produce joule loss, which acts as a heat source to raise the temperature of the iron pot. When designing the heating coil, the main points to look out for are: What kind of magnetic circuit design will raise heating efficiency, and whether it is generating uniform heat in the iron pot. Another factor is controlling leakage flux to the circuit component in the board box that surrounds the apparatus.
A magnetic field analysis simulation that uses the finite element method (FEM) is best for studying a three dimensional combination of the geometry, number, and alignment of the magnetic material that adjusts the magnetic circuit, and for quickly obtaining the electric circuit constant of the high frequency circuit that performs the heating.
This Application Note shows how to obtain the magnetic flux density surrounding an IH cooking heater that uses high frequency induction heating and the temperature distribution of its iron pot.
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 | 44 - Resistance Heating Analysis of a Steel Sheet | Module:HT,TR | 2012-08-31 | In treatments like hot formed pressing, a steel sheet needs to be heated uniformly as a part of pre-processing. Resistance heating is a method of uniform heating that uses a steel sheet's electric resistance. In resistance heating, current is run through electrodes placed on both sides of a steel sheet. The joule heat produced from the ensuing electric resistance is then used to heat the steel sheet. However, the uniformity of the range of heat generation changes depending on the arrangement of the electrodes, so whether or not the uniformity satisfies the heating conditions needs to be investigated ahead of time.
Unevenness in the current distribution flowing from the electrodes through the steel sheet is determined from the geometry and the material's electric conductivity. Electric conductivity changes according to the temperature, though, so both the electromagnetic phenomena and the heat transfer phenomena need to be analyzed at the same time.
This Application Note presents how to obtain the differences in temperature distribution in a steel sheet and temperature increases from applied current.
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 | 42 - Displacement Analysis of a Piezoelectric Actuator
| Module:DS | 2008-11-27 | Piezoelectric elements are used as actuators and sensors, as well as oscillator circuits and filter circuits in the analog electronic circuits. When the electric potential is applied, the piezoelectric element is deformed. This is called the converse piezoelectric effect. In JMAG, the analysis of the piezoelectric actuator using the converse piezoelectric effect can be performed by specifying the permittivity matrix and the electric potential for the material.
This note presents the use of structural analysis to evaluate the displacement of a bimorph piezoelectric actuator, caused by the inverse piezoelectric effect.
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 | 39 - Torque Analysis of a Three Phase Induction Motor Accounting for the Skew
| Module:DP,TR | 2012-07-31 | An induction motor can utilize skew easily because the cage is constructed by metallic casting such as die casting. When skew is applied, it arranges the variations in the magnetic flux that links to the cage in a sinusoidal wave. This makes it possible to eliminate the harmonic components from the induction current that cause negative torque and contain things like the torque variations caused by influence from the slots.
Applying skew generally affects the flow of magnetic flux in the axial direction, making it complex. This is why an analysis that can correctly verify the three dimensional magnetic flux flow is necessary to obtain an advance evaluation of the skew's effects.
This Application Note presents a comparison of the torque waveforms of three phase squirrel cage induction motors with and without torque, and introduces the effects of using skew to reduce torque variations. Changes in the higher components caused by skew are also displayed by separating the frequencies of the secondary current, which causes the torque variations.
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 | 38 - Starting Performance Analysis of a Single Phase Induction Motor
| Module:DP | 2013-02-28 | Single phase induction motors are widely used as small output motors for the drives in household electrical appliances and office machinery, like fans and washing machines, because they can use single phase AC, the typical power source for home electronics. Unlike three phase AC, however, single phase AC cannot create a rotating magnetic field by itself, meaning that it cannot start a motor. For this reason, it needs to use an alternate method to generate a rotating magnetic field to start the motor.
It is important to verify whether or not torque is generated in the intended direction and continues to rotate stably ahead of time in the design phase. In order to carry out this verification, the conditions where the rotor follows the equation of motion according to the electromagnetic force mechanism and starts up need to be analyzed correctly.
The purpose of this Application Note is to introduce an example of a single phase induction motor that uses a capacitor to set up an auxiliary winding and show its rotation speed versus time, torque versus time, and the magnetic flux density distribution and current density distribution in the bar just after the motor starts.
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 | 36 - Operating Time Analysis of an Electromagnetic Relay
| Module:TR | 2013-01-28 | Electromagnetic relays are devices that use an electromagnet to physically connect and disconnect contact points. Magnetic flux is generated from the magnetomotive force, which is expressed as the product of the number of turns in the coil and the current that is applied to the coil. This flux produces an attraction force in the movable core, making the relay close.
To put it simply, the attractive force is determined from the area of the gap between the movable core and the stator core and the size of the magnetic flux density produced in said gap. With a relay whose movable core does not move linearly, however, it is hard to predict the magnetic flux density in the gap because it does not become parallel. The nonlinear magnetic properties of the iron core and yoke also affect the magnetic flux density in the gap. With a JMAG magnetic field analysis, it is possible to obtain the attraction force of the movable core while accounting for these factors.
This Application Note presents the use of the motion equation function to evaluate the operating time of an electromagnetic relay that uses a DC voltage drive.
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 | 34 - Demagnetization Analysis of an SPM Motor
| Module:DP | 2012-07-31 | Rare earth magnets has characteristics of large energy product, but decrease when using in an area exceeding a knee point causing irreversible demagnetization. For motors, the possibility of thermal demagnetization through thermal stress may occur when the magnet temperature rises due to iron loss or copper loss during rotation. Large amounts of electric currents are run through an excitation coil where demagnetization may occur when a reverse magnetic field is applied on a magnet. Demagnetization of magnets in a motor is one of the causes of decrease in motor performance, where whether or not performance has decreased demagnetization needs to be predicted.
The magnetic field analysis simulation can handle magnetic fields or temperature generated in an internal magnet which can evaluate demagnetization on the edges of a magnet accurately.
This note presents the use of a magnetic field analysis to evaluate the demagnetizing ratio distribution of an of an SPM motor by changing the current flow.
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 | 32 - Analysis of a Transformer
| Module:FQ | 2012-07-31 | A transformer is an electrical device that uses electromagnetic induction to convert the voltage level of alternating current power. In an ideal transformer the secondary voltage is constant regardless of the load, but in reality it tends to vary with the size of the load and the power factor. The size of a transformer's voltage variations is a vital output characteristic when considering constant voltage reception. It is also important to maintain a balanced state because an imbalance in the voltage and current in each phase can bring about a rise in the transformer's temperature or a fault in the device using the transformer.
A transformer's output characteristics depend on the leakage flux from the iron core. Leakage flux passes through the air instead of the iron core, so it is hard to predict accurately during the design phase. It is possible to handle magnetic flux passing through the air in a magnetic field analysis, meaning that it is also possible to evaluate a transformer's output characteristics, including the effects of leakage flux.
This Application Note presents the use of a magnetic field analysis to evaluate changes in the secondary voltage caused by load variations in a low frequency transformer.
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 | 31 - Iron Loss Analysis of an SPM Motor Including the Effect of Press-fitting Stress
| Module:DP,DS,LS | 2013-01-28 | The laminated structure of a core in a SPM motor can be sustained using press-fitting or shrink fitting. The press-fitting stress needs to be accounted for in the iron loss evaluation because the stress caused by press-fitting is known to increase the iron losses when a magnetic steel sheet is used for the core of the motor.
An iron loss is generated by the magnetization field in displacement with a steel sheet. The size of the iron loss is dependent on the iron loss properties of a steel sheet. The iron loss characteristics of a steel sheet deteriorates by stress from press fit coupling. The stress generated by the press fit coupling is distributed in areas in which the section in the back yoke becomes large. In order to evaluate the iron loss with good accuracy, it is necessary to obtain the stress distribution for the magnetic flux, time variation, and steel sheet with accuracy.
This note presents the use of the press fit condition to model a core and frame and obtains iron loss density for when the generated stress is used and not used.
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 | 29 - Iron Loss Analysis of an SPM Motor with Overhanging Magnet
| Module:LS,TR | 2013-01-28 | There are times when permanent magnet motors are designed with a magnet made with overhang, in other words made longer than the stator's stack length, in order to strengthen the magnetic field that it creates. A space is necessary in the stator core to supply the coil ends, and there is a wasted space in the rotor if the rotor and stator have the same stack length, so a magnet is placed in this space with the objective of increasing the magnetic flux without making the magnet thicker. However, the magnetic field produced by the overhanging part of the magnet enters the stator at an angle, so magnetic flux is produced in the lamination direction, which creates a possibility of increasing eddy current loss by a wide margin. When the overhang is too big, the magnet's magnetic field goes to waste because it does not reach the stator.
For this reason it is necessary to set up the overhang amount properly while looking at the trade-off between an increase in torque and an increase in losses. A magnetic field analysis using the finite element method (FEM), which can obtain the relationship between a three dimensional magnetic field and eddy currents, is an effective method for an advance study.
This Application Note presents the use of a no-load iron loss analysis of an SPM motor with and without an overhanging magnet.
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 | 28 - Magnetic Field Analysis of a Speed Sensor UP!
| Module:TR | 2013-06-17 | Antilock brake systems (ABS) have become a standard feature in vehicles, so speed sensors are attached to each wheel in order to measure their respective speeds. There are several methods of detecting rotation speed, but magnetic sensors are weather resistant and have a small number of parts because there only needs to be a gear on the rotation side, so they are widely used.
The challenges from a design standpoint are the angle and relative distance between the gear's teeth and sensor, and how to ensure sensitivity and responsiveness when considering the magnetic influence of the surrounding air. In order to proceed with an advance study like this that considers a precise geometry and material properties, an electromagnetic field analysis using the finite element method (FEM) is effective.
This Application Note presents the use of magnetic field analysis to evaluate the variation of the voltage signal of a magnetic speed sensor for a range of air gap distances.
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 | 27 - Head Field Analysis of a Recording Write Head That Accounts for Eddy Currents
| Module:TR | 2013-02-28 | Magnetic heads are devices that are used to record data on storage media, and are often found in hard disks. A magnetic head has both a recording head that writes data by magnetizing a round magnetic disk and a playing head that reads the data from the magnetic disk's magnetization pattern. For the recording head, the vital thing is an evaluation of the recording head field's responsiveness toward input electrical signals. This evaluation comes from a detailed evaluation of the magnetic flux density distribution around the head. To study these characteristics, the analysis needs to include the effect of eddy currents generate on the yoke.
In order to account for eddy current distribution that is produced in the fine part at the tip of the recording write head, a magnetic field analysis using the finite element method (FEM) is most effective.
This Application Note shows how to obtain the responsiveness of recording head field that is generated in the magnetic head.
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 | 26 - Braking Torque Analysis of an Electromagnetic Brake
| Module:TR | 2013-02-28 | An electromagnetic brake is an auxiliary brake device for large-scale vehicles like trucks and buses. It is fit onto the propeller shaft and applies a braking force. There are both hydraulic and electromagnetic types. With an electromagnetic brake, a magnetic field is produced in the stator coil, making eddy currents occur because of time variations in the magnetic flux density linking to the rotor. This, in turn, produces a braking torque. The range in which eddy currents occur in the rotor and the braking torque can vary a great deal according to the current flowing to the stator coil and the rotor's rotation speed.
In order to estimate the electromagnetic brake's performance accurately at the design stage, it is best to carry out an electromagnetic field analysis simulation using the finite element method (FEM) because it can approximate the material's nonlinear magnetic properties and can approximate the skin effect caused by current distribution, as well.
This Application Note shows how to obtain the braking torque of an electromagnetic brake during drive.
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 | 25 - Analysis of a Claw Pole Alternator
| Module:TR | 2013-01-28 | Demand for high fuel efficiency in vehicles has been growing every year, and auxiliary machines like power steering and coolant pumps have been switching to electrical operation to support those needs. This is why the amount of electrical power being used in typical gasoline vehicles is increasing with each passing year, and manufacturers are looking for high-output alternators that can supply this level of electricity. They need to increase the output density, however, because they cannot increase the size of the actuator to correspond with the added generation capacity. They also need to achieve higher efficiency.
A claw pole alternator generates electricity in the coil on the stator side with the rotor side acting as an electromagnet. The excitation coil on the rotor side is a single phase, and the claw pole is arranged so that it wraps around this coil. The claws that extend from the inside of the coil and the ones that extend from the outside of the coil have poles with different polar characteristics, and they have the same polar structure as a magnet that is arranged with magnetization that alternates between North and South. Because the alternator needs to be designed with a 3D geometry to account for the claw poles and the analysis needs to consider eddy currents generated in the surface of the claw poles, which are made from a metal plate, an electromagnetic field analysis using the finite element method would be the most useful, as it can simulate detailed geometries and account for eddy currents.
This Application Note presents the use of an electromagnetic field analysis to evaluate the output capacity of a claw pole alternator operating at 1500 rpm while accounting for eddy currents in the rotor core.
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 | 24 - Cogging Torque Analysis of an SPM Motor with a Skewed Stator
| Module:TR | 2013-01-28 | Reductions in vibration and noise are being sought after because they are a cause of torque variations in motors, and demands for reduction are particularly strong with motors that are used in machine tools and power steering. Cogging torque, which is a torque variation that is produced when there is no current, is generated because the electromagnetic force, which is produced in the gap, changes in relation to the rotor's rotation, making it necessary to apply skew to the stator and rotor and improvise with the magnet and stator's geometry in order to limit said variations in electromagnetic force as a countermeasure for reducing the torque variations. When applying skew, force in the thrust direction is produced in exchange for a reduction in the cogging torque, meaning that there is the disadvantage of producing eddy currents from the magnetic flux that links in the lamination direction.
Consequently, in order to accurately evaluate a motor that has skew applied, one needs a magnetic field analysis simulation that uses the finite element method (FEM), which can account for a detailed 3D geometry, instead of studies that use the magnetic circuit method or a 2D magnetic field analysis.
This note presents the use of magnetic field analysis to evaluate the cogging torque of an SPM motor with a skewed stator.
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 | 22 - Analysis of the Eddy Current in the Magnet of an IPM Motor
| Module:TR | 2013-01-28 | More and more permanent magnet motors are starting to use rare earth magnets, which have a high energy product, in order to achieve higher output density. Neodymium rare earth magnets contain a great deal of iron so they have a high electric conductivity, but when a varying magnetic field is applied they produce Joule loss from eddy currents. Due to the spread of IPM structure adoption and field weakening controls in recent years to speed up rotation, the frequencies and fluctuation ranges of varying fields applied to magnets have increased, and there has been a corresponding increase in Joule loss. By dividing the magnet, like one would a laminated core, to control eddy currents, one can obtain a method of raising the apparent electric conductivity and lowering the eddy currents. Armature reactions in the stator occur before the eddy currents produced in the magnet, so the eddy currents are determined by the slot geometry of the stator core, the geometry of the rotor, the nonlinear magnetic properties of the core material, and the current waveform that flows through the coil.
In order to examine these kinds of magnet eddy currents ahead of time, one has to account for things like these geometries and material properties precisely, so a magnetic field simulation using the finite element method (FEM), which can account for them, would be the most effective.
This Application Note presents the use of a magnetic field analysis in a state of operation to obtain variations in magnet eddy current losses according to the number of divisions in the magnet.
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 | 21 - Iron Loss Analysis of an SPM Motor Including the Effect of Shrink Fitting
| Module:DP,DS,LS | 2013-01-28 | A magnetic steel sheet is used for the iron core in a motor. A frame is shrunk into a stator core in order to sustain the laminated structure and to improve the strong joint between the frames. It is know that a compressive stress is generated during the shrinking process which increases the iron loss process. Therefore, it is important to account the affects of stress during iron loss evaluation. Therefore, it is important to account the affects of stress during iron loss evaluation.
An iron loss is generated by the magnetization field in displacement with a steel sheet. The size of the iron loss is dependent on the iron loss properties of a steel sheet. Iron loss characteristics of a steel sheet deteriorates when there is stress in shrinkage. The stress generated by the shrinkage is distributed in areas in which the section in the back yoke becomes large. In order to evaluate the iron loss with good accuracy, it is necessary to obtain the stress distribution for the magnetic flux, time variation, and steel sheet with accuracy.
This note presents an analysis to obtain the iron loss density of an SPM motor both including and not including the stress caused by shrink fitting.
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 | 20 - Sound Pressure Analysis of an SPM Motor
| Module:DP,DS | 2012-07-31 | As electric motors are becoming more common, motors which create less noise are in high demand. Sound can be divided into categories of electromagnetic noise, mechanical noise, and draft noise, where electromagnetic noise is the most common for medium and small sized motors. Sound can be divided into categories of electromagnetic noise, mechanical noise, and draft noise, where electromagnetic noise is the most common for medium and small sized motors.
The electromagnetic force in a motor vibrates as an electromagnetic excitation force which creates noise. The vibration and noise are generated when the electromagnetic excitation force resonates with the motor's eigenmodes. In order to evaluate this phenomenon more accurately, it is necessary to understand the distribution of electromagnetic force that moves the stator core which is the basis for the radiated sound. The distribution of electromagnetic force or the eigen modes in a model that depends on the geometry of a stator core is required for running an analysis such as for the finite element analysis.
This Application Note shows an example of an evaluation of a reactor's sound pressure, when acquiring electromagnetic force generated by a stator core for a SPM motor and linking the eigen modes of a motor.
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 | 19 - Analysis of the Centrifugal Force in an IPM motor
| Module:DS | 2013-01-28 | While motors have started being combined with motor drives and used in a wide range of velocities, further changes toward high output and high efficiency are being demanded of them. While high speed revolution has been given as a means of attaining a higher output, the magnets have a weaker intensity than the steel sheets, so evaluations from the standpoint of mechanical strength are necessary because the centrifugal force grows large during rotation.
IPM motors have a structure that embeds the magnet in the rotor. Centrifugal force kicks in during motor drive, so the magnet becomes pressed against the rotor core because it gets peeled off or displaced, making it so that a strong local stress begins to operate. It is necessary to correctly handle the phenomena of a magnet peeling off or becoming displaced in order to accurately obtain the local stress distribution. It is important to account for the adhesion and contact conditions between the magnet and rotor core in an analysis in order to do this.
This Application Note presents examples of cases that obtain changes and stress distribution from the centrifugal force in the rotor when the magnet is both fully and partially adhered to the rotor core.
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 | 18 - Thermal Analysis of an IPM Motor
| Module:HT,LS,TR | 2012-07-31 | Exactly how to resolve the problem of rising temperatures is a critical issue when trying to achieve an improvement in a motor's efficiency and output. In order to solve this problem it is important to investigate a magnetic design that reduces the losses themselves because they are a source of heat, but it is also important to study a thermal design that improves heat dissipation and does not let the temperature rise. Copper loss in the coils and iron loss in the core are the dominant heat sources, so this analysis mainly evaluates the effects of this heat. Changes in the magnet's properties due to temperature are large and its heat resistance is low, so it is necessary to design while paying careful attention to rising temperatures during operation. During operation, rated evaluations with a continuously operated constant load are run until a thermal balanced state has been reached. In addition to these rated evaluations, however, thermal transient evaluations that add a thermal cycle with an intermittently operated electrical overload are performed, as well.
In order to carry out an accurate thermal design, it is necessary to first correctly understand the heat generation amount and location, so it would be advantageous to calculate the losses in a magnetic field analysis simulation using the finite element method, and from there to carry out a thermal analysis using the resulting loss distribution.
This Application Note explains how to evaluate a motor's temperature distribution by creating a thermal analysis model that can investigate the loss analysis and temperature distribution in order to obtain the motor's total loss distribution, and then analyzing the elevated temperature process.
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 | 16 - Analysis of a Hybrid Stepper Motor
| Module:TR | 2013-01-28 | Hybrid stepper motors are used as actuators for equipment where position detection accuracy is required, such as the joints of robots or rotary tables for machine tools. The rotor has a construction that sandwiches a magnet that is magnetized in the axial direction between two rotor cores that have serrated teeth to create salient poles, and the tips of the stator core's teeth are shaped like gears as well. The rotation resolution is determined by the number of gears in the rotor and the number of phases in the drive coil, so the number of gears is set to rather large numbers like 50 and 100 to raise the angle resolution. The most important characteristics for a stepper motor are the controllability, the detent torque, which is a non-excitation holding torque, and the stiffness torque, which is an excitation holding torque, and not the motor's output.
The two-plated rotor core of a stepper motor has an N pole on one side and an S pole on the other, so a multipole magnet is achieved by deviating the saliency of the gear condition by 1/2 pitch. Consequently, the magnetic circuit is 3D. There are also times when the division pitch geometry of the teeth is complicated, so it is necessary to carry out a 3D electromagnetic field analysis using the finite element method (FEM) to proceed with an accurate preliminary study.
This Application Note describes how the detent torque and stiffness torque can be calculated for a hybrid stepper motor.
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 | 15 - Cogging Torque Analysis of an SPM Motor with a Step Skewed Magnet
| Module:TR | 2013-01-28 | Reductions in vibration and noise are being sought after because they are a cause of torque variations in motors, and demands for reduction are particularly strong with motors that are used in machine tools and power steering. Cogging torque, which is a torque variation that is produced when there is no current, is generated because the electromagnetic force, which is produced in the gap, changes in relation to the rotor's rotation, making it necessary to apply skew to the stator and rotor and improvise with the magnet and stator's geometry in order to limit said variations in electromagnetic force as a countermeasure for reducing the torque variations. When applying skew, force in the thrust direction is produced in exchange for a reduction in the cogging torque, meaning that there is the disadvantage of producing eddy currents from the magnetic flux that links in the lamination direction.
Consequently, in order to accurately evaluate a motor that has skew applied, one needs a magnetic field analysis simulation that uses the finite element method (FEM), which can account for a detailed 3D geometry, instead of studies that use the magnetic circuit method or a 2D magnetic field analysis.
This Application Note presents the use of magnetic field analysis to evaluate the magnetic flux density distribution and cogging torque in each part of an SPM motor with a step skewed magnet.
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 | 14 - Inductance Analysis of a Busbar
| Module:FQ,Pi | 2010-08-31 | Voltage surges can damage the components in electrical equipment such as an inverter.
Busbar inductance can be a cause of surges. Therefore, it is important to reduce it to protect the electrical equipment.
Using FEM allows for the calculation of inductance based on the magnetic field and current distribution obtained from the magnetic field analysis.
This note presents a case study on the current distribution and the frequency versus inductance characteristic of the busbar.
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 | 13 - High-Frequency Induction Heating Analysis of a Shaft | Module:FQ,HT | 2012-08-31 | Shafts are used in parts like axles, which transfer power from the engine to rotate the tires, so the need to have sufficient strength to handle the torsion. They also need to have increased surface toughness to raise their degree of abrasion resistance in the areas that join with other parts, and they must maintain their interior toughness in order to obtain strength and fatigue resistance against torsion. By using high-frequency induction heating, which is a type of surface hardening method, the part is heated rapidly on only its surface by a high frequency power source. This process also has many other benefits, such as providing a clean working environment because it uses electrical equipment, being very efficient, and providing uniform results for each product. This is why it is being aggressively implemented in the field.
Eddy currents generated by the high-frequency varying magnetic field occur in the surface of the shaft. The material properties also change due to the rising temperature. Examining detailed phenomena requires handling the phenomena that occur in the interior of the shaft in a numerical analysis based on the finite element method.
This Application Note explains how to create a numerical analysis model and analyze the elevated temperature process in order to use the coil geometry and current conditions (power supply frequency, current value) to verify whether or not the target temperature distribution is obtained.
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 | 10 - Thermal Analysis of a Radiant Heater
| Module:HT,TR | 2012-04-10 | Quartz heaters, which are used in semiconductor manufacturing, are a kind of heating device that uses heat radiation phenomena. Thermal radiation is a mechanism of heat transfer, which is defined as the transport of heat through the transmission of electromagnetic waves between objects that have different temperatures, making transfer possible even through a vacuum. This objective is to transfer heat to a heated body uniformly by placing it near the heater, which has been heated by running current through the coil.
It is necessary to properly handle the effects of the 3D geometry of the heated body or the heat generated from the heater in order to see whether it is raising the temperature uniformly, so a thermal analysis is carried out.
This Application Note explains how to carry out a thermal analysis using the thermal radiation phenomenon between a heater and a heated body to obtain the differences in temperature distribution in the heated body with and without a shield.
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 | 9 - Sound Pressure Analysis of a Loudspeaker
| Module:DS,TR | 2013-04-26 | A loudspeaker produces sound when the voice coil makes the vibrator vibrate. The general requirement of the loudspeaker is to produce uniform sound over a wide range of the frequencies.
Lorentz force is generated in the coil when the magnetic field of a permanent magnet acts on the current flowing through the voice coil, and produces sound by making the vibrator vibrate. In order to evaluate the sound with good accuracy, it is necessary to handle the resonance phenomenon between the Lorentz force and the speaker's eigenmode properly. The eigenmode and Lorentz force distribution change depending on the place where the core and coil are wound, so high accuracy calculations need to be carried out using the finite element method (FEM).
This Application Note presents how the frequency characteristics of sound pressure can be obtained using the constant Lorenz force on the voice coil, regardless of the frequency.
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 | 8 - Analysis of an Axial Gap Motor
| Module:TR | 2013-02-28 | Unlike typical cylindrical motors such as radial gap motors, axial gap motors have a structure in which the stator and the rotor, which is arranged on a disk, face each other and produce rotation. For that reason, because it is possible to arrange thinner parts than with a radial gap motor, they can respond to demands for miniaturization of equipment.
With axial gap motors, evaluations using the magnetic circuit method and empirical data are difficult because the magnetic flux that passes through the rotor and stator, which face each other, becomes a 3D magnetic circuit, meaning that a 3D electromagnetic field simulation using the finite element method (FEM) is necessary because it can carry out an accurate analysis.
This Application Note shows how to use JMAG's 3D magnetic field analysis to carry out a load analysis of an axial gap motor, and then obtain the Speed-Torque curve and the Torque-Current curve.
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 | 7 - Analysis of a Spindle Motor
| Module:TR | 2013-02-28 | Spindle motors are often used as drive motors where limited space is an issue, as is the case with storage media like hard disks. They employ an outer rotor structure in order to obtain a large torque, but to do so they have to use a great deal of permanent magnets while remaining thin and compact. In order to reduce the number of parts used in their composition, the rotor core has functions that both bear the magnet's flux path and transfer the generated torque, which supports the magnet, to the shaft. For this reason the rotor core is composed of materials that are easy to produce, meaning that there is a possibility that its efficiency as a magnetic circuit will decrease. As motors get smaller, they require a design that accounts for flux leakage because it begins to affect the disc in the rotor.
For this reason, spindle motors need electromagnetic field simulations that use the finite element method (FEM), which can account for detailed 3D geometry and magnetic saturation in materials, in order to carry out an accurate evaluation.
This Application Note shows how the Speed-Torque curve, the Torque-Current curve and the magnetic flux density distribution of a spindle motor can be obtained.
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 | 4 - Sound Pressure Analysis of a Reactor
| Module:DS,TR | 2013-04-26 | Reactors are used in a variety of electric power systems. For instance, they fill the role of making the current pulsation between an inverter and a motor more smooth. On the other hand, the sound that originates from a resonance phenomenon between an electromagnetic force and an eigenfrequency can become a problem.
The reactor in this analysis has a gap in the magnetic circuit to prevent magnetic saturation. Due to the magnetic fields that occur with high frequency currents, electromagnetic force generates near the gap, and this electromagnetic excitation force in turn causes noise. Vibration and sound grow larger when the electromagnetic excitation force and the transformer's eigenmode resonate. In order to evaluate this phenomenon with good accuracy, it is necessary to find the electromagnetic force distribution and eigenmode in the high frequencies that become particular problems by using the finite element method (FEM).
This Application Note shows an example of an evaluation of a reactor's sound pressure when a part of a spacer has been removed.
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 | 3 - Analysis of a Permanent Magnet Brush Motor
| Module:DP | 2013-01-28 | A brush motor generates torque through the electromagnetic attraction and repulsion between its rotor and stator. They do not have many parts and do not require drive circuits, so they are widely used as a power source for compact equipment. A brush motor is composed of a magnetic circuit part, which actually generates torque via electromagnetic phenomena, and the brush/commutator part, which corresponds to the drive circuit. In order to aim at improving the performance of a brush motor, it is necessary to raise the usage efficiency of the magnetic circuit in each part and expertly utilize the nonlinear material characteristics. Proper placement of the brush/commutator that correspond to the drive circuit is also vital.
In order to evaluate the usage efficiency of the magnetic circuit, torque variations, current waveforms, etc. at the design stage, it is best to first do a detailed calculation of the magnetic flux density in each part, and then perform an electromagnetic field simulation using the finite element method (FEM), which can evaluate torque with high accuracy.
This note presents how the characteristics of the brush-type PM motor can be obtained, including torque versus current (T-I), torque versus speed (T-N), and magnetic flux density distribution.
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 | 2 - Cogging Torque Analysis of a PM Linear Motor
| Module:TR | 2013-01-28 | Linear motors have been widely used in carrier devices and the drive units of machine tools due to their capability for high acceleration and deceleration, as well as their accurate positioning. As an issue for improving performance, people are trying to obtain a large thrust force in order to enhance responsiveness, but on the other hand it is also necessary to fulfill the demand for the trade-off of wanting to reduce thrust force variations and the attraction force.
In order to obtain a large thrust force, the material's nonlinear magnetic properties and the magnet's demagnetization characteristics need to be accounted for, and in order to evaluate thrust force variations, they need to be analyzed after modeling a detailed geometry. This is why they need to be studied with a magnetic field analysis simulation based on the finite element method (FEM).
This note presents how to obtain cogging torque, a cause of thrust variation, and evaluate the thrust force and attraction force during drive.
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 | 1 - Torque Characteristic Analysis of a Three Phase Induction Motor
| Module:DP | 2013-04-26 | An induction motor is a motor in which the rotating magnetic field of the stator coils causes induced current to flow in an auxiliary conductor, exerting force on the rotor in the rotational direction and causing it to spin. Induction motors are widely used in everything from industrial machines to home appliances because they have a simple construction and are small, light, affordable, and maintenance-free.
In an induction motor, the current induced by the auxiliary conductor exerts a large influence on its characteristics. It also causes strong magnetic saturation in the vicinity of the gap, in particular. With Finite Element Analysis (FEA), it is possible to investigate the characteristics that accurately evaluate the features listed above, so preliminary design evaluations are effective.
This Application Note introduces a case example of how to obtain the current density distribution of an auxiliary conductor and its rotation speed versus torque characteristics.
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